i took piano lessons when i was a runt...about 5 years worth...it was great - i can still read music at 45

then i picked up a gibson epiphone campfire model in 1972 (which i still have and sonny boy uses) and taught myself guitar listening to dylan and neil young and tom waits

today i can play a song (rudimentarily) by just hearing it...i can figure out the chords in a couple seconds (which is no big deal really), but for piano, i have to have sheet music (which i play poorly)

so my question is: how do i get myself to a point where i can tinkle on the piano without sheet music? i've tried just toodling chords and filling in with notes in between, but it doesn't sound good...there's gotta be some trick i am missing